Di-neoalkyl beta, beta, beta1, beta1-tetraloweralkyl-substituted alkylene dicarboxylates



United States Patent DI NEOALKYL 6,13,5 ,5 TETRALOWERALKYL- SUBSTITUTEDALKYLENE DICARBOXYLATES Albert M. Durr, Jr. and Harold H. Eby, PoncaCity,

Okla and Melvin S. Newman, Columbus, Ohio, assignors to Continental OilCompany, Ponca City, Okla a corporation of Delaware No Drawing. Originalapplication July 16, 1962, Ser. No. 210,198. Divided and thisapplication Jan. 12, 1965, Ser. No. 425,083

2 Claims. (Cl. 260-485) This application is a division of applicationSerial No. 210,198, filed July 16, 1962, which was a continuationin-partof application Serial No. 747,587, filed July 10, 1958, and nowabandoned.

This invention relates to ester-type materials which are suitable foruse as synthetic lubricants. More particularly, the invention relates toester-type materials which are derived from acids in which the carbonatom alpha or beta to the carboxyl group is completely substituted withacyclic alkyl groups. Preferably, the sub stituted carbon atom is thealpha carbon atom.

Military use of turbojet and turboprop aircraft engines has led to aneed for specialized engine lubricants. These lubricants must permitstarting at very low temperatures encountered in arctic bases. They alsomust have adequate lubricity and stability at very elevatedtemperatures. Modern engines have exceedingly high power for their sizeand put a severe heat stress on the lubricant.

The mineral lubricating oils which possess satisfactory low temperatureviscosities have generally been found to have flash points that aredangerously low and high temperature viscosities that are below thoserequired. In other words, when the mineral oil is thin enough at lowtemperatures, it is too thin and too volatile at higher temperatures. Inaddition, conventionally refined mineral oils deteriorate too rapidly athigh operating temperatures, even when compounded with the bestavailable antioxidants.

needed for these turbine-type engines, synthetic lubricants have beendeveloped. Esters represent a class of materials which have attractedunusual interest as synthetic lubricants. Diesters are a preferred classof esters. These materials are generally characterized by high viscosityindexes and flash points and lower pour points than mineral oils of acorresponding viscosity.

While the diesters offer many outstanding properties which enable themto be used as lubricants for turbojet and turboprop engines, thereremain characteristics in which they may be improved. Two suchcharacteristics are thermal stability and hydrolytic stability,

In the more recent turbines, the normal hearing temperatures duringoperation reach as high as 475 F. With bearings next to the turbinewheel, a soak-back effect occurs following shutdown. Heat accumulated inthe turbine wheel disk flows into the cooler turbine bearings when theoil flow is stopped at time of shutdown. This may add another 100 to 150F. for a brief period following shutdown. The resulting temperatures arehigher than can be withstood by conventional diesters, regardless ofcompounding with additives. Lack of thermal stability in these materialsresults in (a) engine deposits and (b) physical loss of lubricant due topartial volatilization of decomposition products.

Since all oil systems in aircraft collect small amounts of Water fromtime to time, a diester lubricant should have hydrolytic stability. Lackof hydrolytic stability results in formation of volatile alcohols andcorrosive 40 Recently, in an effort to obtain the superior lubrlcantsacids. Currently availaible diesters are not adequately stable.

Broadly stated, the present invention relates to estertype materialswhich are derived from organic carboxylic acids in which the carbon atomalpha or beta to the carboxyl group is completely substituted withacyclic alkyl groups. In one embodiment the invention relates todiesters which are derived from dicarboxylic acids in which the carbonatoms alpha to each of the carboxyl groups is completely substitutedwith acyclic alkyl groups, and from either conventional monohydroxyalcohols or from monohydroxy alcohols in which the beta carbon atomthereof is completely substituted with alkyl groups or fluorine atoms.In a further embodiment. the invention relates to diesters which arederived from dicarboxylic acids in which the carbon atoms beta to eachof the carboxyl groups is completely substituted with acyclic alkylgroups and from monohydroxy alcohols in which the beta carbon atomthereof is completely substituted with either acyclic alkyl groups orfluorine atoms. In another embodiment the invention relates to estersprepared from monobasic acids in which the carbon atom adjacent to thecarboxyl group is completely substituted with acyclic alkyl groups andpolyhydroxy alcohols in which the beta carbon thereof is completelysubstituted with acyclic alkyl groups. In still another embodiment theinvention relates to the novel dicarboxylic acids in which the carbonatoms alpha or beta to each of the carboxyl groups is completelysubstituted with acyclic alkyl groups. In yet another embodiment theinvention relates to a process for preparing the afore-mentioneddicarboxylic acids. In yet still another embodiment the inventionrelates to complex esters which are prepared from (a) theafore-mentioned dicarboxylic acids, (b) the afore-mentioned monobasicacids, (c) the afore-mentioned polyhy'droxy alcohols and (d) theafore-mentioned monohydroxy alcohols.

Before proceeding to a description of the suitable starting materialsfor these ester-type materials, it may be well to set forth anexplanation of the heory associated with the function of thesematerials. While we do not wish to be bound by this explanation, webelieve the theory is as follows:

Thermal degradation of esters formed from aliphatic alcohols andaliphatic acids is initiated at the carbonyl oxygen and results in theformation of olefin and acid. This degradation arises from electronmigration after formation of an unstable ring structure. To form thisintermediate ring there must be hydrogen atoms in the alcohol portion ofthe ester which are in the sixth atom position from the carbonyl oxygen.These hydrogen atoms must also be coplanar to the carbonyl group or musthave rotational freedom if ring formation is to occur. The action isindicated by the following diagram:

Esters in which the six positions of the alcohol portion are completelysubstituted with alkyl groups prea vent thermal elimination through thismechanism because the formation of the above foregoing ring structure isnot possible and no hydrogens are available in the six position fortransfer.

Alkyl groups on the alpha carbon of the acid portion of an estermolecule sterically hinder and reduce the availability of the carbonyloxygen for attack by oxygen, hydrogen, acids, or bases. In other words,the presence of such alkyl groups improves the hydrolytic stability ofthe ester molecule. The greater the size of the alkyl substituent, thegreater would be the hindrance and, accordingly, resistance tohydrolysis. Methyl groups in the alpha position to the carbonyl carbonmeet the minimum requirements.

Alcohols with alkyl groups or fluorine atoms on the carbon atom beta tothe hydroxyl group, and acids in which the carbon atoms either alpha orbeta to the carboxyl groups are completely substituted with alkylgroups, are referred to as hindered alcohols and acids. Esters preparedfrom alcohols and acids, both of which are hindered, possess boththermal and hydrolytic stability. If only the alcohol is hindered, theester possesses only thermal stability. If only the acid is hindered,the ester possesses only hydrolytic stability.

We have found that substitution only on the beta carbon atoms of thedicarboxylic acid does not produce a noticeable or measurable effect onhydrolytic stability. Still further, we have found that esters preparedfrom hindered alcohol and dicarboxylic acids in which the carbon atoms,either alpha or beta to the carboxyl groups, are completely substitutedwith alkyl groups exhibit thermal stability greater than is shown whenonly the alcohol is hindered. This discovery is surprising.

Before giving specific examples of the products and processes of thepresent invention it may be well at this time to describe the nature ofthe materials used and the processes involved.

In order to set forth clearly the nature of the present invention theterm ester as used herein and in the claims refers to the productderived by reacting an organic carboxylic acid with an organic hydroxycompound.

The hindered dibasic acids of the present invention have one of thefollowing formulas:

wherein R is an acyclic alkyl group containing from 1 to 4 carbon atoms,n is an integer varying from 1 to 10, and n is an integer varying from 1to 9.

Examples of suitable dibasic acids in which the carbon atom alpha to thecarboxyl group is completely substituted with acyclic alkyl groups arethe following:

Suberrc acids:

2,2,7,7-tetraethyl* 2,7-dimethyl-2,7-diethyl 2,7-dimethyl-2,7-dipropyl*2,7-diethyl-2,7-dipropyl 2,7-diethyl-2,7-dibutyl 2,2,7,7-tetramethyl*2,2,7,7-tetrapropyl 2,2,7,7-tetrabutyl Azelaic acids:

2,2,8,8tetraethyl* 2,8-dimethyl-2,8-diethyl* 2,8-dimethyl-2,8-dipropyl*2,8-diethyl-2,8-dipropyl 2,8-diethyl-2,8-dibutyl* 2,2,8,8-tetramethyl2,2,8,8-tetrapropyl 2,2,8,8-tetrabutyl 2,2,8,8-tetraisopropyl2,2,8,S-tetratertiarybutyl Sebacic acids:

2,2,9,9-tetraethyl* 2,9-dimethyl-2,9-diethyl 2,9-dimethyl-2,9-dipropyl*2,9-diethyl-2,9-dipropyl 2,9-diethyl-2,9-dibutyl* 2,2,9,9-tetramethyl*2,2,9,9-tetrapropyl 2,2,9,9-tetrabuty1 Examples of suitable dibasicacids in which the carbon atom beta to the carboxyl group is completelysubstituted with acyclic alkyl groups are the following:

Beta acids:

3,3-dimethyl glutaric acid 3,3,5 ,5 -tetramethyl pimelic acid3,3,6,6-tetramethyl suberic acid* 3,3,6,6-tetraethyl suberic acid3,6-dimethyl-3,6-diethyl suberic acid" 3,3,7,7-tetramethy1 azelaic acid3,3,8,8-tetramethyl sebacic acid Of the suitable acids listed above, theones indicated with an asterisk are preferred. Of the preferred acids,the ones indicated with a double asterisk are more preferred.

Diesters having improved hydrolytic stability are exceedingly difficultto prepare directly from hindered acids because the hindrance impedesreaction with the alcohol. We have prepared these diesters from the acidchloride of the hindered acid and the sodium salt of the alcohol used.

Diesters prepared from hindered alpha-substituted dibasic acids andconventional alcohols have the following formula:

wherein R is an acyclic alkyl group containing from 1 to 4 carbon atoms,R is an acyclic alkyl group containing from 1 to carbon atoms and n isan integer varying from 1 to 10. Examples of suitable conventionalalcohols are the following:

n-Butanol n-Dodecanol n-Hexanol n-Tridecanol n-Octanol* n-Hexadecanoln-Decanol*= n-Octadecanol Z-ethylhexanol 2-ethy1 butanol IsooctanolIsodecanol Of the suitable alcohols listed above, the ones indicatedwith an asterisk are preferred.

Diesters prepared from hindered dibasic acids and hindered alcohols havethe following formula:

where A is selected from wherein R is an acyclic alkyl group containingfrom 1 to 4 carbon atoms, R is an acyclic alkyl group containing from2to 10 carbon atoms, X is either fluorine or an acyclic fiuoroalkyl groupcontaining from 1 to 10 carbon atoms, where B is selected from:

wherein R is an acyclic alkyl group containing from 1 to 4 carbon atoms,n is an integer varying from 1 to 10, and n is an integer varying from 1to 9.

The hindered alcohols of the present invention have one of the followingformulas:

where R is an acylic al-kyl group containing from 1 to 4 carbon atoms, Ris an acyclic alkyl group containing from 2 to 10 carbon atoms, and X iseither fluorine or an acyclic fluoroalkyl group containing from 1 to 10carbon atoms.

Examples of suitable hindered alcohols are the following:

2,2-dimethyl-1-pentanol* 2,2-diethyl-1 butanol* 2,2dimethyl- 1-heXanol*2,2-dimethyl-1-butanol Z-methyl-Z-ethyll-octanol2,2,4-trimethyl-l-pentanol 2,2-dimethyl-1-octanol* 2,2dimethyl-l-decanol* Z-methyl-Z-propyld -pentanol 2-ethyl-2-propyl-1-hexanol2-methyl-2-tertiary amyl-l-butanol 2-methyl-2-isopropyl-1-hexanol1H,1H,7H-dodecafluoro 1-heptanol 1H,1H,9H-hexadecanefluoro-l-nonanol1H,1H,1lH-eicosafiuoro-l-undecanol Of the suitable alcohols listedabove, the alcohols with acyclic alkyl substituents on the beta carbonatom are preferred. Of these latter alcohols the ones indicated with anasterisk are more preferred.

Some of the hindered alcohols in which the beta carbon atom iscompletely substituted with alkyl groups are available commercially. Theothers can be prepared in the laboratory. The preparation of2,2-dirnethyl-1- hexanol is shown below:

PREPARATION OF 2,2-DIMETHYL-l-HEXANOL 1. Intermediate (1) Sodiumtriethylmethoxide (C H COH+NaNHg (C2H5)3CON3 (2) Dimethylacetyl chloride(CH CHC(O OH+SOCl (CH CHCO Cl where C(O) is 0:0

(3) Triethylcarbinyl isobutyrate C H CONa+ (CH CHCOC1 3)z l z 5)a 2.2,2-dimethyl-1-hexan0l The hindered monobasic acids of our inventionhave the formula:

wherein R R and R are acyclic alkyl groups containing from 1 to 18carbon atoms. Examples of suitable hindered monobasic acids are thefollowing:

Of the above suitable hindered monobasic acids the ones indicated withan asterisk are preferred.

The hindered polyhydroxy alcohols of our invention have the followingformula:

wherein A has a formula selected from the group consisting of:

wherein R, R and R are acyclic alkyl groups containing 1 to 4 carbonatoms and n is an integer varying from 1 to 10.

Examples of suitable hindered polyhydroxy alcohols are the following:

GLYCOLS 1,3-propanediols:

2,2-dimethyl* 2,2-diethyl* 2,2-dipropyl 2,2-dibutyl 2-methyl-2-ethyl*2-methyl-2-propyl* 2-methyl-2-buty1* 2-ethyl-2-propyl Z-ethyl-Z-butyl1,6-hexanediols:

2,2,5,5-tetramethyl* 2,6-dimethyl-2,6-diethyl* 2,6-dimethyl-2,6-dipropyl2,6-dimethyl-2,6-dibutyl 2,6-diethyl-2,6-dipropyl* 2,2,5 ,5 -tetraethylt2,2,5,5-tetra'butyl 2,5,5-trimethyl-2-propyl-3ethyl2,2,5,S-tetramethyl-3,4-diethyl 1,7-heptanediols:

2,4,6-trimethyl-2,6-dipropy1 2,2,4, 6,6-pentamethyl-3-ethyl1,8-octanediols:

2,7,7-trimethyl-2-propyl 2,2,4,5,7,7-hexarnethyl2,2,7,7-tetramethyl-3-ethyl 2,2,4,7,7-pentamethyl 1,10-decanediols2,2,9,9-tetramethyl* Of the above suitable hindered polyhydr-oxyalcohols the ones indicated with an asterisk are preferred.

Esters prepared from hindered monobasic acids and polyhydroxy alcoholshave improved hydrolytic and thermal stability. These materials have thefollowing formula:

wherein R R and R are acyclic alkyl groups containing from 1 to 18carbon atoms and where A is selected from the group consisting of:

R4 R4 R: I a I J and |(CH ),,('3- R4 R4 R4 wherein R is an acyclic alkylgroup containing from 1 to 4 carbon atoms and n is an integer varyingfrom 1 to 10.

Complex esters can be prepared from the hindered alcohols, hindereddibasic acids, and hindered polyhydroXy alcohols of the presentinvention. These complex esters possess improved hydrolytic stability.They can be shown diagrammatically as follows:

where A equals hindered monohydroxy alcohol, B equals hindered dibasicacid, and A equals hindered polyhydroxy alcohol; and

where B equals hindered dibasic acid, A equals hindered polyhydroxyalcohol, and D equals hindered monobasic acid.

The hindered dibasic acids per se which form an embodiment of ourinvention have been described previously.

Our invention relates also to the process for preparing the hinderedalpha-substituted dibasic acids. This process can be described ascomprising the following steps.

(a) Synthesis of the intermediates (1) Preparation of diethylacetylchloride:

(C H CHC(O)OH+SOCl (C H CHC(O)CI (2) Preparation of sodiumtriethylmethoxide:

liq. N H3 (C2H5)3C OH NaNH (C2H5)3C ONa (3) Preparation oftriethylcarbinyl Z-ethylbutyrate:

(b) Synthesis of di(triethylcarbinyl) 2,2,8,8-tetraethylazelate Na (C H1C(O)OC(C2H5)3+ BromomcI-nomcmm OHZCH2C CZH5 2C (O)OC(C2H5)3 CH2 z 2 022 5)a (0) Preparation of 2,2,8,8-tetraethylazelaic acid CHzCHzC (02115):(O)OC(C2H5)3 dioxane z z 2 02 O C (0 119 E? I 2 20 (C2 5)2C O OH CHHBCHBC (C2H5)2C O OH While the purpose of this invention is to providematerials which are especially useful in the formulation of lubricantsfor use in turbojet and turboprop engines, the novel diesters hereindescribed may find use in wide temperature range greases, hightemperature heat transfer fluids, hydraulic fluids, and lubricants forprecision instrument bearings. The novel diesters of this invention are9 materials which provide hydrolytic stability to an extent hithertounknown.

Conventional diesters were used as standards for comparison with thehindered diesters of this invention. Diisooctyl azelate, di-Z-ethylhexylsebacate, and diisobutyl azelate are commercially available diesterswhich were used per se. Di-2-ethylhexyl azelate is also commerciallyavailable, but the material used was purified by vacuum distilling, toobtain a center cut, and then filtering through alumina. Dl-n-octylazelate was prepared from commercially available materials. Itspreparation is shown in the examples.

In order to disclose the nature of the present invention still moreclearly, the following illustrative examples will be given. It is to beunderstood that the invention is not to be limited to the specificconditions or details set forth in these examples except insofar as suchlimitations are specified in the appended claims.

Example I.Preparatin of di-n-octyl azelate Apparatus.One-liter,three-necked, round-bottomed flask; Trubore stirrer; thermometer;Barrett water trap; reflux condenser; heating mantle; separatory funnel(two liters).

Procedure-Charged 188.2 grams of azelaic acid, 325.0 grams of l-octanol,2.0 grams of toluenesulfonic acid, and 150 cc. of benzene to thereaction flask. Heat was applied and stirring commenced. Refluxinitially was at 95 C. and continued for 8 hours, at which time thereflux temperature had risen to 110 C. During this period, 36 ml. ofwater was removed and collected in the water trap. The reaction mixturewas then transferred to a Separatory funnel and washed with 2 x 250 ml.portions of 5 percent aqueous sodium carbonate solution. It was thenwashed with 5 x 250 ml. portions of tap water until the pH (via Hydrionpaper) was 7. The crude diester was dried over anhydrous magnesiumsulfate and then filtered through a one-inch cake of Hyfio filter aid.The filter aid was washed with 100 ml. of benzene and the benzene wasadded to the product layer. The crude mixture (653 grams) was charged toa simple vacuum distillation setup. Using a water aspirator, benzenesolvent was removed. Using a vacuum pump, a forecut which includedexcess alcohol was removed at 0.65 mm. Hg up to a vapor temperature of187 C. At 0.07 mm. Hg 364.0 grams of diester (di-n-octyl azelate) wascollected. A cut distilling between 202-235 C. at 0.17 mm. Hg weighed18.2 grams. The bottoms weighed 7.5 grams. The diester cut waspercolated through 104 grams of alumina. The filtrate had an acid numberof 1.2 and a saponification number of 269. The acid number was furtherreduced to 0.02 by percolation through basic ion exchange resin.

Example II.Preparalion of di 2,2-dimethylhexyl azelate Prepared inaccordance with synthesis steps outlined in previous discussion.

A pparatus.-Two-liter, three-necked, round-bottom flask; Truborestirrer; thermometer; Barrett water trap; water-cooled reflux condenser.

Procedure-To the reaction flask were charged 141.8 grams of2,2-dimethyl-l-hexanol, 104.5 gr'amsof azelaic acid, 250 cc. of benzene,and 2 grams of p-toluenesulfonic acid. This mixture was heated withstirring at reflux for 8 hours, during which time 20.5 cc. of water wascollected in the Barrett trap. In an additional 8 hours of heating atreflux with stirring, no additional water was collected. The reactionmixture was transferred to a separatory funnel and washed with 2 x 100cc. portions of sodium carbonate solution which emulsified; but afterstanding overnight, it separated when 400 cc. of ether was added. Thisethereal layer was then washed with 2 x 100 cc. portions of water, driedover calcium sulfate, and filtered through a three-inch cake grams ofalumina). The alumina was washed with 150 m. of ether. The etherealfiltrate and the ether wash of the alumina were combined and stripped ofbenzene and ether up to 100 C. on a water aspirator. At 0.14 mm. Hgusing a vacuum fractionation setup, 163.4 grams of di-2,2-dimethylhexylazelate was separated between 176191 C. vapor temperature. A forecut (10grams) and the still bottoms (14 grams) were also obtained. The yield ofthe diester based on the alcohol charged is 72.5 percent. The acidnumber of the distilled diester was 0.76. The acid number was reduced to0.04 by percolation through basic ion exchange resin.

Example lII.Preparati0n of di-2,2-diethylbulyl azelate Materials MolesGrams 2,2-diethyl-1-butanol O. 121. 5 Azelaic acid 89. 4 Benzene (250cc.) p-Toluenesulfonie a 2.0

ther- (650 cc.)

Prepared in accordance with synthesis steps outlined in previousdiscussion.

A pparatus.-Same as in Example II.

Pr0cedure.-The procedure was the same as used in Example II. A yield of148.3 grams (76.5% of theory based on alcohol charged) of product wasobtained. The boiling range of the product was 185-192 C. at 0.12 mm. ofmercury. The distilled diester had an acid number of 0.97. The acidnumber was reduced to 0.02 by percolation through basic ion exchangeresin.

Example I V.-Preparati0n of di-2,2-dimetizylamyl azelate Materials MolesGrams Archie acid 0.5 94 2,2-dimethyl-1-pentanol 1. l 128p-Toluenesulfonic acid 2 Ben ene (200 cc.)

, percent by volume with pentane, was percolated through alumina andthen a 12-inch column of the basic ion exchange resin (IR45). Pentanewas removed up to C. at .1 mm. Hg. The acid number of this undistilleddiester was 0.03. It weighed 170 grams (88.5 percent yield).

The second batch was prepared using the same procedure except that thediester was distilled. The di(2, Z-dimethylamyl) azelate distilledbetween 180 C at .1 mm. Hg pressure.

The acid number of the dis- (A) Preparation of2,2,8,8-tetraethylazelaoyl chloride Materials Moles Grams2,2,8,8-tetraethylazelaic acid 1 Thionyl chloride Benzene (solvent) 1Prepared in accordance with synthesis steps outlined in previousdiscussion.

Apparatus.Two-liter, three-necked flask; Trubore stirrer; refluxcondenser; thermometer.

Prcedurc.Charged 76.7 grams of thionyl chloride to the dry reactionflask along with 84.7 grams of 2,2, 8,8-tetraethylazelaic acid and 450cc. of benzene. Stirring was commenced and the mixture heated at 78 C.until hydrogen chloride gas evolution ceased (eight hours). The crudemixture was stripped of excess thionyl chloride and benzene atatmospheric pressure up to 122 C. pot temperature. On house vacuum atmaximum pot temperature of 118 C., remaining traces of light ends wereremoved. The acyl halide bottoms which solidified on cooling weighed 92grams (theoretical 95 grams). This product analyzed 17.5 percent C1(theoretical 21).

(B) Preparation of di(n-octyl)-2,2,8,8-tetraethylazelate Materials MolesGrams Ferric nitrate (catalyst for amide prepara- Apparatus.Two-liter,three-necked, round-bottomed flask; Trubore stirrer; Dry Ice-cooledcondenser; bubble counter; drying tube; dropping funnel.

Procedure.--Charged 1,000 cc. of ammonia to the dry nitrogen-flushedreaction flask; then 0.5 gram of sodium metal was added. After thesolution turned blue, the liquid was blown with dry air until the colorwas discharged; then 1.0 gram of ferric nitrate was added. Stirring wascommenced, and the remaining 22.2 grams of sodium metal was added insmall portions over a period of 2.0 hours. The temperature of thereaction flask was held at -35 C. Ten minutes after the addition of thesodium was completed, the blue color was discharged. To this mixture wasadded dropwise 128.5 grams of l-octanol diluted with 300 cc. of dryether. After the final addition of l-octanol, an additional 200 cc. ofdry ether was added. Ammonia was allowed to evaporate overnight; thennitrogen was blown through the pot mixture, which was heated on a steambath for five hours. During this period, 500 cc. of ether was added.Next, 166.2 grams of 2,2,8,8-tetraethylazelaoyl chloride in 300 cc. ofdry ether was added at such a rate as to maintain constant reflux andcontrol the reaction. Poststirring was continued for three hours. Icewater (500 cc.) was added cautiously over 30 minutes. The mixture wasfiltered to remove a small quantity of flocculent which hamperedseparation of the water and ether layers. The two layers were thenseparated and the ether Wash of the aqueous layer was combined with theether layer. The ether layer was Washed with 2 x 200 cc. portions ofpercent sodium hydroxide and finally with water until the wash water wasneutral to pHydrion paper. The ether layer was filtered through aone-inch cake of Hyflo filter aid and dried over calcium sulfate. Etherwas removed by heating to 60 C. at atmospheric pressure after filteringthrough grams of alumina. The crude diester was charged to a vacuumdistillation setup and stripped up to 200 C. at 0.1 mm. Hg pressure. Themaximum vapor temperature during this period was 68 C. Overhead weighed16.7 grams. The bottoms product Weighed 232.5 grams. The product diesterwas diluted 50 percent by volume with pentane and percolated through 180grams of alumina followed by a 12-inch column of basic ion exchangeresin (IR-45). Both columns were flushed with pentane and the wash addedto the eflluent diester. Pentane was removed up to C. at 0.1 mm. Hgpressure. The product diester weighed 177.5 grams. This product had anacid number of 0.02 and analyzed 75.0 percent carbon (theoretical 75.7)and 12.2 percent hydrogen (theoretical 12.2).

Example VI.Prcparation of di-2,.2-dimethylamyl-2,2, 8,8-tetmethylazelate(A) Preparation of 2,2,8,B-tetraethylazelaoyl chloride 1 Prepared inaccordance with synthesis steps outlined in previous discussion.

Apparatus.Two liter, three-necked flask; Trubore stirrer; refluxcondenser; thermometer.

Procedure.Charged grams of thionyl chloride to the dry reaction flaskalong with 154 grams of 2,2,8,8- tetraethylazelaic acid in 500 cc. ofbenzene. Stirring was commenced, and the mixture was heated at 78 C.until hydrogen chloride gas evolution ceased (12 hours). The crudemixture was stripped of excess thionyl chloride and benzene atatmospheric pressure up to 125 C. pot temperature. On house vacuum atmaximum pot temperature of 118 C., remaining traces of light ends wereremoved. The acyl halide bottoms weighed grams (theoretical 174 grams).

(B) Preparation of di-(2,2-dimethylamyl)-2,2,8,8-tetraethylazelateApparatus.Two liter, three-necked flask; Trubore stirrer; Dry Ice-cooledcondenser; bubble counter; drying tube; dropping funnel.

Procedure-Charged 1,000 cc. of ammonia to the dry nitrogen-flushedreaction flask; then 0.5 gram of sodium metal was added. After thesolution turned blue, the liquid was blown with dry air until the colorwas discharged. One gram of ferric nitrate was added. Stirring wascommenced, and the remaining 22.5 grams of sodium was added in smallportions over a period of one hour. The temperature of the reactionflask was held at 35 C. Ten minutes after the addition of sodium wascompleted, the blue color was discharged. To this mixture was addeddropwise 116 grams of 2,2-dimethylpentanol diluted with 300 cc. of dryether. After the final addition of 2,2-dirnethylpentanol, ammonia wasallowed to evaporate overnight. Nitrogen was blown through the reactionmixture, which was heated on a steam bath for six hours. Two hundred cc.of ether was added followed by 170 grams of 2,2,8,8-tetraethylazelaoylchloride in 300 cc. of dry ether at such a rate as to maintain constantreflux and control the reaction.

13 Poststirring was continued for three hours at full reflux. Ice water(750 cc.) was added cautiously over /2 hour. The mixture was filtered toremove fluocculent material and transferred to a separatory funnel inwhich two tube removed. The U-tube was then inserted, flushed withnitrogen, and a slight positive nitrogen pressure allowed to remain. Thetube was immersed in an aluminum block bath and heated to 550 C. for 48hours.

layers formed. The water layer was removed and washed 5 The acid numberswere then determined by means of a with 200 cc. of ether and the etherwash combined with Precision Automatic Titrator, using AST M procedurethe ether layer. The ether layer was washed with Water D66454. until theresulting water wash was neutral to pHydrion In calculating the percentdecomposition, as shown in paper. The ether layer was dried overnightover calcium Table III, the saponification number was assumed to besulfate, filtered through alumina, and stripped of ether equivalent to100 percent decomposition.

O up to 60 C. at atmosphericpressure. The cmde d ester HydrOlyn-cstability testing was charged to a vacuum distillation setup andstripped up to 192 Q at 025 mm Hg pressure, Th maximum Timedsapomfication numbers were made on both the vapor t mperature was 23 C.The product diester (botreference diesters and the hindered diesters.The time toms) was diluted 50 percent by volume with pentane IntervalsChosen hour, 2 hours, 4 hours, 21111 d percolated h h a 124 b Column f bi i 24 hours. The saponification numbers were determined exchange resin(IR-45). The column was washed with 115mg ASTM Procedure pentane and thewashings combined with the product- Physical tests containing layer.Pentane was removed up to 115 C. v at 0.3 mm Hg pressure The productWeighed 198.5 The various physical tests conducted used standard grams.The acid number of the diester was 0.64. ASTM Procedures ABLEI.ANALYTICAL DATA ON HINDERED ALC TESTING PROCEDURES (EXAMPLES IVI) THOLS AND ACID 0F EXAMPLES 0 Thermal stability testing 25 Boiling Thethermal stability of each of the esters prepared Melting Boilil lgp0int.C. Acid N0. was determined using a simple test. A 25-ml. sample of(Lltemme) the ester to be tested was charged to a tube cm. long, 1 25cm. in diameter, fitted With a side arm 8 cm. from %f EH36 233;? the topof the tube to which was attached through a 30 22d, th 11 75 H4 82 U4standard taper joint a U-tube containing mercury. The i gif I fi top ofthe test tube was fitted with a 24/40 standard i g *93 5 H 2 taper jointin which was fitted a stopcock with an S-mm. mm g g ID. tube e.tendininside the test u x E k t be to i 10 cm JACS,55,1121(1933). of thebottom. T e stopcoc was opened, nitrogen gas 35 1103,78, 5415 wasintroduced, and the testing tube flushed w1th the U- 3 Gauge notCahbtated- TABLE II PHYSICAL PROPERTIES OF DIESTERS SHOWN IN EXAMPLESI-VI Viscosities Refractive Example Viscosity ASTM Density index atNumber Diester index slope at 25 C. 25 0.,

Cs. at Cs. at Cs. at NaD -40 F. 100 F. 210 F Conventional;

Diisooctyl azelate 1, 285 12. 54 3. 38 164 0. 686 0. 9131 1. 4488D1-2-etl1yll1exyl sebacate. l, 400 12. 80 3. 34 154 0.706 0. 9106 1.4492 Diisobutyl azelate- 254 5. 58 1. 1 0.802 0.9281 1. 4348 IDi-n-oetyl azelate- Solid 11. 32 3. 25 175 0.674 0. 9091 1. 4472Di-Z-ethylhexyl azelate 1, 242 10.96 2. 99 145 0. 676 0. 9135 1. 4481Hindered:

Di-2,2-dimethylhexyl azelate 4, 722 15. 90 3. 65 133 0.725 0. 9093 1.4471. Di-2,2-diethylbutyl azelate s, 343 21. 03 4. 43 1, 414 0. 700 0.9323 1. 4555 Di- 2,2-dimethylamyl azelate (redistilled) 3, 140 13. 26 3.23 125 0. 736 0. 9151 1. 4451 D1-n-octyl-2,2,8,8-tetraethylazelate Notrun 43.27 5. 33 104 0. 736 0.9082 1.4560Di-2,2-dimethylamyl-2,2,8,8-tetraethyl azelate Not run 118.00 8. 620.832 0.9113 1.4545

TABLE TIL-THERMAL STABILITY STUDIES (EXAMPLES IVI) [25 n11. sampleheated in nitrogen atmosphere for 48 hours at 550 F.]

Acid No. after- Percent 2 decomposition Saponifica- Example Diester AcidNo. tion Num- Number (Before) her, mg.

Run No. 1 Run N0. 2 Run No. 1 Run N0. 2 KOH/gm.

Conventional:

Diisooctyl azelate 0. 02 72 26. 5 34. 9 272 Di-2-ethylhexyl sebacate. 0.04 43 53 16.2 19. 9 266 Diisobutyl azelate 0. 01 57 61 15. 5 16. 6 368 iI Di-n-octylazelate 0.03 49 67 17.8 24.4 275 Di-Z-etliylhexyl azelate 0.07 47 40 17. 3 14. 8 271 Hindered:

Di-2,2-di1nethylhexyl azelate 0. 04 4. 4 4. 9 1. 6 1.8 273Di-2,2-diethyll)utyl azelate. 0. 02 7. 1 5. 9 2. 6 2. 1 275Di-2,2-di1nethylarnyl azelate- 0. 01 13 13 4. 4 4. 4 295Di-n-octyl-2.2,8,8-tetraethyl azela 0. 03 56 20.2 3 214Di-2,2id1;metl1ylamyl-2,2,8,8-tetraethyl 0. 04 8 3.5 3 226 1 Acid numberin mg. KOH/grn. 2 decomposition is equal to saponification number. 3Theoretical.

TABLE IV.HYDROLYTIO STABILITY STUDIES (EXAMPLES I-VI) SaponifieationNumber, Example Acid mg. KOH/gm. Number Diester Number 2 hours 4 hours24 hours Theoretical Actual (30 minutes) Conventional:

Diisooctyl azelate 0.02 272 272 Di-2-ethylhexyl scbacate 0. 04 262 266Diisobutyl azelate 0. 01 334 308 Di-n-octyl azelate 0. 03 272 275Di-Z-ethylhexyl azelate 0.07 272 271 Hindered:

Di-2,2-dimethylhexyl azelate O. 04 272 273 Di-2,2-diethy1butyl azelate0.02 272 275 Di-2,2-dimethylamyl azelate 0.01 292 296Di-n-octyl-2,2,8,8-tetraethyl 0. 03 214 18 25 22 33Di-2,2-dimethylamyl-2,2,8,8-tetraethyl azclate 0. 64 226 19 19 21 76Example VII.Preparati0n of 2,2,8,8-tetraethylazelaic acid (A)Preparation of 2-ethy1butyryl chloride Materials Mole Moles Quantity,

weight g.

2'ethylbutyric acid 116.16 1, 743 Thionyl chloride, Eastman grade.-."118. 98 1G. 8 2,000

(B) Preparation of triethylcarbinyl 2-ethylbutyrate Materials Mole MolesQuantity weight Ferric nitrate 1 g. Ammonia, anhydrous 2,000 cc Sodium,purified lump 0 Triethylcarbinol, Eastman grade Z-ethylbutyryl chlorideEther, anhydrous reagents Pr0cedure.Sodiurn amide was prepared from 140grams of sodium and 2 liters of liquid ammonia, using ferric nitrate ascatalyst. Triethylcarbinol (969 grams) in 300 cc. of dry ether wasslowly added to the reaction mixture. The ammonia was allowed toevaporate, and the mixture was refluxed in a stream of nitrogen for 12hours. Approximately one liter of dry ether was added during this time.

A solution of 807 grams of Z-ethylbutyryl chloride in 200 cc. of etherwas added dropwise to the reaction mixture. This was then stirred forone hour and heated under reflux for another hour. Water was added todissolve the solids. The ethereal solution was washed with 10 percentsodium hydroxide, washed with water until neutral, and dried overcalcium sulfate. Fractional distillation of the crude mixture yielded1067 grams (83.5 percent) of triethylcarbinyl Z-ethylbutyrate (RR 102-105 C. at 10 mm).

(0) Preparation of di-(triethylcarbinyl)2,2,8,8-tetraethylazelateMaterials Mole Moles Quantity weight Ferric nitrate 1 g. Ammonia,anhydrous 2,000 cc Triethylcarbinyl 2-ethylbutyrate 214 5 1,067 g1,5-dibromopentane, Eastman grade 229. 97 2. 5 575 g. Sodium, purifiedlump 22. 997 5 155 g Ether, anhydrous reagent- 600 cc Procedure-Sodiumamide was prepared from 115 grams of sodium and 2 liters of liquidammonia. Triethylcarbinyl Z-ethylbutyrate (1067 grams) was addeddropwise, and the mixture was stirred for 1.5 hours. A solution of 575grams of dibromopentane in 200 cc. of ether was added dropwise, andstirring was continued for 1.5 hours. More ether (400 cc.) was added,and the ammonia was allowed to evaporate. After refluxing the solutionone hour, water was added to dissolve the solids present. The etherealsolution was washed with water until neutral, dried over calciumsulfate, and reduced to small volume under vacuum. The crude residueweighing 1002 grams was hydrolyzed without further purification.

(D) Hydrolysis of di-(tricthylcarbinyl)2,2,8,8-tetraethylazelateMaterials Mole Moles Quantity weight Di (triethylcarbinyl)2,2,8,8-tetra-496 2. 02 1,002 g.

ethylazelate. Hydrochloric acid, concentrated 36. 5 5. 35 450 cc.

reagent. Dioxane, commercial 500 cc Examp le VIII.-Preparation ofZ-methyl-Z-ethyl-I- pentanol (A) Preparation of 2-1nethy1pentanoylchloride Materials Mole weight Moles Grams 2-methylpentanoic acidThionyl chloride Pr0cedure.To 1457.5 grams of thionyl chloride in a drynitrogen-flushed flask, Z-methylpentanoic acid (1242 grams) was addeddropwise with stirring. The temperature was maintained at 3545 C. Afterthe addition was completed, the temperature was raised to C. When gasevolution had ceased, the material was fractionated at atmosphericpressure. Z-methylpentanoyl 17 chloride (1176 grams, 82.5 percent)distilled at 137- 139 C.

(B) Preparation of triethylcarbinyl 2-methylpentanoate Materials MoleMoles Quantity weight Ferric nitrate 1 g. Ammonia 2,000 cc. Sodium 22.997 6. 1 140 g. Triethylcarbinol 116 6 696 g. Z-methylpentanoyl chloride134.6 6. 13 825 g. Ether 3,000 cc.

Prcedure.To 2000 cc. of liquid ammonia in a dry nitrogen-flushed flaskwas added 0.5 gram of sodium metal. The blue color was discharged with astream of dry air; then 1 gram of ferric nitrate was added. Theremaining sodium (139.5 grams) was added in small portions withstirring. To this mixture was added a solution of 696 grams oftriethylcarbinol in 500 cc. of dry ether. The ammonia was allowed toevaporate overnight, and the reaction mixture was then treated with astream of nitrogen and heated under reflux for 15 hours, 15 00 cc. ofether being added to the reaction rflask during this time.

Next, a solution of 825 grams of 2-methylpentanoyl chloride in 200 cc.of ether was added dropwise over a 4 h'0ur period. Stirring wascontinued for 1 hour. Water (l15'00 cc.) was slowly added. The contentsof the flask were filtered, and the product was extracted with ether.The ether solution was washed with two 250-cc. portions of 1 0 percentsodium hydroxide and then with water until the wash water was neutral,dried over calcium sulfate, filtered, and freed of solvent atatmospheric pressure. The residue was vacuum fractionated. The product,triethylca-rbinyl 2-methylpentanoate (930 grams; 72.5 percent) distilledat 92-101 C. at Hg.

(0) Preparation of triethylcarbinyl 2-methyl2-ethylpentanoatePr0cedure.To 2000 cc. of liquid ammonia in a dry nitrogen fiushed flaskwas added 1.0 gram of sodium. The blue color was discharged with astream of dry air; then 1.0 gram of ferric nitrate was added. Theremaining sodium (99 grams) was added in small portions with stirring.To this mixture, triethylcanbinyl Z-methylpentanoat-e (930 grams) wasadded dropwise. continued tfior two hours after the addition wascompleted. Next, a solution of 474 grams of ethyl bromide in 300 cc. ofether was added dropwise. The ammonia was allowed to evaporate, andether .(1100 cc.) was added to facilitate stirring. Sufficie-nt Water(about 1500 cc.) was added to dissolve the solids formed. The contentsof the flask were filtered, and the product was taken up into ether. Theether solution was washed with water until neutral, dried over calciumsulfate, filtered, and freed of solvent at atmospheric pressure. Theresidue was fractionated. The overhead temperature was taken to 115 C.at 12 mm. Hg. The residue (705 grams) was reduced to the alcohol withoutfurther treatment.

Stir-ring was Pr'0cedure.A mixture of grams of lithium aluminum hydrideand I1000 cc. of dry ether in a dry nitrogenflushed flask was stirredand heated under reflux 'for 5 hours using a steam bath.Triethylcarbinyl 2-met'hyi-2- ethylpentanoate (705 grams) was addeddr-opwise to the reaction mixture. Following the final ester addition,the mixture was refluxed for 16 hours. Water was added very slowly untilhydrogen evolution ceased; then 50 percent H SO was added until thesolution was acidic. Additional water had to :be added to completesolution of the solids in the flask.

The product was taken up into ether, washed with two 1500-cc. portionsof 10 percent sodium hydroxide and with water until neutral, dried overcalcium sulfate, filtered, and freed of solvent at atmospheric pressure.The residue was vacuum fractionated. Triethylcanbinol weighing 80.4grams dis-tilled at 7682 C. at 48 mm. Hg. 2-methyl-2-ethyl-1-pentanol(345 grams; 65 percent) distilled at 80-90" C. at 25 mm. Hg.

Example IX.-Preparation ofdi-(Z-methyl-Z-ethylpemfyl)2,2,8,8-tetraethylazelate Preparation of2,2,8,8 tetraethylazelayl chloride Materials Mole Moles Quantity weight2,2,8,8-tetraethylazelaic acid 300 522 150. 5 g. Thionyl chloride,Eastman grade.-- 118. 98 1. 31 156. 5 g. Benzene, AOS rea ent 200 cc.Pyridine, reagent 2 drops.

Acylation of 2-methyl'2-ethylpentanol with 2,2,8,8-tetraethylazelaylchloride Materials Mole Moles Quantity Weight Ferric nitrate 1 g.Ammonia 1,500 cc. 2methy1-2-ethylpentanol 1 88 245 g. 2,2,8,8-tetraethylazelayl chloride 337 94 Ether 2,500 cc. Sodium 22.997 1. 88 43.2 g.

Pr0cedure.-To 1500 cc. of liquid ammonia in a dry nitrogen-flushed flaskwas added 0.5 gram of sodium metal. The blue color was discharged with astream of dry air; then 1 gram of ferric nitrate was added. Theremaining sodium (42.7 grams) was added in small portions with stirringover a two-hour period. To the sodium amide mixture a solution of 245grams of 2-methyl-2- ethylpentanol in 400 cc. of dry ether was addedslowly. The ammonia was allowed to evaporate overnight. The mixture wasrefluxed for eight hours while a stream of nitrogen was passed throughit, 500 cc. of dry ether being added to the reaction mixture during thistime. Next, the tetraethylazelayl chloride prepared from 0.94 mole ofacid was dissolved in 500 cc, of dry ether and added dropwise to thereaction mixture at such a rate as to maintain constant reflux. This wasthen refluxed for one hour, and water (1500 cc.) was added. The contentsof the flask were filtered, and the product was taken up into ether,washed with two 250-cc. portions of 10 percent sodium hydroxide and withwater until neutral, dried over calcium sulfate, filtered through Hyflo,and freed of solvent at atmospheric pressure. Volatile materials wereremoved by heating the mixture to 195 C. (vapor temperature: 88 C.) at0.5 mm. Hg pressure. The product ester was the residue (436.5 grams; 89percent).

The residue was refluxed for two hours with 400 cc. of 0.5 N alcoholicpotassium hydroxide. The temperature of the reaction mixture was about78 C. Next, pentane and water were added, and the organic layer waswashed with water until neutral, filtered through Hyfio, and reduced tosmall volume using a water aspirator. The infrared spectrum of thesample showed that it was free of anhydride. Acid number of the productwas 0.32. In order to reduce the acid number, the ester was diluted withpentane and percolated through a 12-inch column of basic AmberliteIR-45. The pentane was removed by heating to 120 C. under oil pumpvacuum. After filtering through a small inch-thick cake of Hyflo, theester was still slightly hazy. It was dried over calcium sulfate forseveral days and filtered again. The product weighed 340 grams and hadan acid number of 0.16. After another treatment with IR-45, the acidnumber was 0.04. Gasliquid partition chromatography indicated that themajor component comprised 79.4 percent of the sample.

Example X.Preparation of di-(2,2-dimethylhexyl)2,2,8,8-zetraethylazelate Materials Mole Moles Quantity weight2,2-dimethy1hexanol-1 130 4. 62 600 g. Tetraethylazelayl chloride 337 10. 75 Ether- 500 cc. Sodium- 22.997 1. 52 35 g.

1 Theory.

Procedure-To 600 grams of refluxing 2,2-dimethylhexanol-l in a dryflask, sodium (35 grams) was added in small portions over a period of2.5 hours. The mixture was refluxed for one hour, and then a solution of0.75 mole of crude tetraethylazelayl chloride in 300 cc. of dry etherwas added dropwise. The temperature of the reaction mixture remained at7080 C. during the acid chloride addition without external heating.Refluxing was continued for two hours after the addition. Enough waterwas added to dissolve the solids formed. The product was taken up inether, washed twice with 250 cc. of aqueous 10 percent sodium hydroxideand by water until neutral, dried over calcium sulfate, and reduced tosmall volume at atmospheric pressure. Remaining volatile materials werethen removed by heating to 200 C. at 0.5 mm. Hg pressure. Weight of theresidue was 378 grams {(96 percent).

Example XI.Preparatin 0f di-(2,2-dimethyl0ctyl)2,2,8,8-tetraetlzylazelate This product was prepared by the same procedureas used in Example X.

Example XII.Preparati0in of di-(2,2-dimcthyldecyl)2,2,8,8-tetraethylazelate This product was prepared by the sameprocedure as used in Example X.

Example XIII .Preparation of di-(2,2-dimethylhexyl)2,2,6,6-tetramethylpimelate 2,2,6,6-tetramethylpimelic acid was preparedby a pro cedure similar to that used in Example VII.

The ester was prepared by a procedure similar to that used in ExampleIX.

Example XIV.Preparati0n of 2,8-dimethyl-2,8-dipr0pyl-- azelaic acid (A)Preparation of di-(triethylcarbinyl)2,S-dimethyl-Z,S-dipropylazelatePr0cedure.$0diun1 amide was prepared from 115 grams of sodium and 2liters of liquid ammmonia using ferric nitrate as catalyst.Triethylcarbinyl 2-methylpentanoate (1072 grams) was added dropwise, andthe mixture was stirred for two hours. A solution of 575 grams of1,5-dibromopentane and 500 cc. of ether was added dropwise, and stirringwas continued for one hour following the addition. Allowing the ammoniato evaporate overnight resulted in loss of part of the reduction mixturethrough foaming. The mixture was heated for one hour to expel remainingammonia, and suflicient water was added to dissolve the solids in theflask. The product was taken up into ether, washed with water untilneutral, and dried over calcium sulfate. The solution was filtered andfreed of solvents by distillation at atmospheric pressure. Distillationat 10 mm. pressure yielded 103 grams at 4095 C. and 106 grams oftriethylcarbinyl 2-methylpentanoate at 97101 C. The crude product(residual) weighed 882.5 grams and was hydrolyzed without furtherpurification.

(B) Hydrolysis of di-(triethylcarbinyl)2,S-dimethy1-2,8-dipropylazelateProcedure-To a refluxing solution of 882.5 grams crude di(triethylcarbinyl)2,8 dimethyl 2,8 dipropylazelate in 500 cc. ofdioxanewas slowly added concentrated hydrochloric acid (400 cc.). Afterrefluxing two hours, azeotropic distillate was collected which separatedinto about 700 cc. of an olefinic layer and 280 cc. of dioxane.Additional dioxane (250 cc.) was added to the reaction mixture. Thecontents of the flask were then poured into two liters of water, and theoily product was allowed to crystallize overnight. The solid wascollected on a filter, washed with pentane to remove color,recrystallized from aqueous 10 ethanol-methanol, and washed withpentane. Three crops were obtained. The

Example X V.-Prepamtin 0f di-(2,2-dimethylhexyl)2,8-dimethyl-2,8-dipropylazelate This product was prepared from2,2-dimethylhexanol and the acid prepared in Example XIV by a proceduresimilar to that used in Example IX.

Example X VI .Preparation of 2,8-dimethyl2,8-diethylazelaic acid Thismaterial was prepared by a procedure similar to that used in ExamplesVII and XIV.

Example XVII.Preparati0n of di-(2,2-dimethylhexyl)2,8-dimethyl-2,8-diethylazelate This product was prepared from2,2-dimethylhexanol and the acid prepared in Example XVI by a proceduresimilar to that used in Example 1X.

Example X VIII .-Preparati0n of di-(1H,1H,7H-d0decafluoro-Z -heptyl2,2,8,8-tetraethylazelate Materials Mole Moles Quantity weight2,2,8,8-tetraethylazelayl chloride 337 l 1 337 g} Pyridine 79. 1 1. 4 C7Fluoroalcohol 1. 4 Benzene, AOS reagent 1 Estimated. 2 Theory.

Pr0cedure.--A mixture of 115 grams of pyridine and 100 cc. of benzenewas slowly added to a solution of the crude 2,2,8,8-tetraethylazelaylchloride and 1'50 cc. of benzene. After refluxing for one hour, amixture of 447.5 grams of C7 fluoroalcohol and 100 cc. of benzene wasadded slowly. The temperature was maintained at approximately 75 C.during the addition. The reaction mixture was then refluxed for threehours. A crystalline material formed in the flask during this time.Sufiicient water was added to dissolve the solids present, andsufficient pentane was added to cause the organic layer to float. Theorganic layer was washed with dilute hydrochloric acid, water, and 10percent sodium hydroxide. A large amount of a heavy red liquid settledto the bottom of the separatory funnel with each sodium hydroxidewashing. This lower layer, weighing 261 grams, was found to be thefluoroalcohol. When no more fluoroalcohol separated during the sodiumhydroxide washing, the organic layer was washed with water untilneutral, and dried. An attempt was made to distill the solvents andother volatile materials from the crude ester, but copious acidic fumeswere evolved. The crude ester was then filtered through alumina, butacid fumes were evolved again when the product was heated to 195 C.under 0.75 mm. pressure. The infrared spectrum indicated presence ofconsiderable anhydride.

After treating three timess with dilute methanolic potassium hydroxide,the infrared spectrum showed no anhydride. The acid number was 0.67, butit had not proved susceptible of reduction by the base treatment.Gas-liquid partition chromatography furnished an assay of 95.8 percent.

22 Example XIX-Preparation of di-(2,2-rlimethyl0clyl)3,3-dimethylglufarate This product was prepared from commerciallyavailable 2,2-dimethyloctanol and 3,3-dimethy1gultaric acid by aprocedure similar to that used in Example IX.

Example XX .Preparation of iii-(2,2-dimethylhcxyl)3,3,6,6-tetramethylsuberate This product was prepared by the followinggeneral procedure:

(1) 3,3-dimethylglutaric anhydride was prepared from 3,S-dimethylglutaric acid,

(2) 3,3-dimethylglutaric anyhdride was converted to methyl hydrogen3,3-dimethylglutarate,

(3) Dimethyl 3,3,6,6-tetramethylsnberate was prepared from methylhydrogen 3,3-dimethylglutarate,

(4) Dimethyl 3,3,6,6-tetramethylsuberate was transesterified with2,2-dimethylhexanol to form di-(2,2-dimethylhexyl) 3 ,3,6,6-tetramethylsuberate.

Example XXl.-Preparation 0 2-methyl-2-ethyl-1,3- propanedioldi-(2,2-dietlzylpentan0rzte) (A) Preparation of 2,2-diethylpentanoieacid 2,2-diethylpentanol was converted to 2,2-diethylpentanoie acidaccording to the procedure of J. Kenyon and B. C. Platt (J. Chem. Soc.,633, 1939). Yields of 53 and 48 percent were obtained. A typicalpreparation was as follows:

Materials Mole Moles Quantity,

weight g.

2,2-diethylpentanol-1 144 1 144 NaOH analytical reagent 40 0.75 30 KMnOanalytical reagent 158 2 15 340 S0 commercial Pr0cedure.-Potassiumpermanganate (340 grams) in 3000 cc. of water was added slowly to awell-stirred mixture of 144 grams 2,2-diethylpentano1 and 30 gramssodium hydroxide dissolved in 250 cc. of water. After twelve hours, theheat of reaction had dissipated. The mixture was then heated to C. forone hour. Gaseous sulfur dioxide was introduced into the solution untilit was acidic and the manganese dioxide went into solution. The organiclayer formed was taken up in ether, washed well with water, and driedover Drierite. The filtered solution yielded 84 grams of2,2-diethylpentanoic acid, distilling at 133137 C. at 17 mm. Hgpressure. The yield was 53 percent, based on alcohol. Acid number:calculated, 354; observed, 348.

(B) Preparation of 2,2-diethylpentanoyl chloride Materials Mole MolesQuantity weight 2,2-diethylpentanoic acid 1.08 g. Thionyl chloride,practical 2 238 g. Pyridine, purified 2 2 drops.

- Analysts 77 1952 pages 915932, or

1 ma d 1 t1 2,241 tl 1- (O) Acylatlon orz-mettllgilazlgyllsghlorirglreopane 10 W1 1 w W Petroleum Refiner,November 1955, pages 165-169.

4 1 H In addition to the data shown, infrared spectra were Mammals gfiMO es Quan 1 y determined on the various esters.

5 TESTING PROCEDURES (EXAMPLES VIIXXVII 1"6 0. 98 172glggtlgilggl-lgarllseg,ggggiiffidiol 118 gg i Thermal stability m'glass(copper present) 1 'd' if yn me pm A ZO-gram sample of the ester isplaced 1n a tube 60 10 cm. long and 2.5 cm. in diameter and fitted witha side arm 8 cm. from the top of the tube to which is Prsolcfizz/25332;}lgtllilfiiglriaf gygocghglr1Z lg attached througga sttlandardtfapehr joint at [lg-tube Colfjlild was 0 t t t t u 50 grams of2-methY1-2-ethY1-1firropanedml- The r fnci ti iger jo int io hi eh isfit t e d a s top co ck with action mixture was externally heated duringthe addition, an 8 mm tube extending inside the test tube to and sol dbegan forming at 88 C. It was then heated within 10 cm. of the bottom.The stopcock is opened,

a a 1 t 't' t se was added. and the product w taken up ether, washesilfminfiifi ifafiiiillid healed 30 663 13331 48 2.52 with hydrochloylq ahil d llfh g 5;? The weight loss due to volatility, the percentviscosity neutral dned Over F q dlstl g1 h 1 6 change, and the acidnumber increase are noted. Per- 2 Y 1,3 d1 let yopcntanoa centagedecomposition is calculated from the acid numwelghlggh 9-1 d gg dlstlne:3 2 ber increase, using the theoretical saponification num- 6 X WasParcen F on a c her as representative of 100 percent decomposition. Theliquid partition chromatography indicated that the ester 25 test wasConducted in the presence of a 1 by 6 cm coppgr was Percent homogeneous'strip. The weight change of the copper is determined.

Example XXII .Preparation of 2-methyl-2-cthyl-L3- Th l stability i steelpropanedmldl'lcdezhybz'lsopmpylhexanoate) A 20-m1. sample of the esteris placed in a cylinder 7 Thi d t was prepared b th f ll i generalinches long made from three-quarter-inch stainless Steel procedure:tubing. A gauge is attached for pressure reading. The bomb is sealedunder one atmosphere of nitro en and y f j y chlorldi Was Prepared fromimmersed in an aluminum block bath for 6 hours at 600 exarlolc aCl F.(316 C.). The gauge pressure durin the test'and f i iifii iii fiofifiifi ?ififi iieahii$555 -Z fli Pemnmg; Yiscgsitt chzmge i? the acinum er lncrease are 0 tame ercentage ecom: Tflethylcafblnyl 1 1 P PY Wasposition is calculated from the acid number increase using p p l1fromfltrleflflylcafblllyl z'ethylheXanofite and the theoreticalsaponification number as representative of P PY foml 100 percentdecomposition. (4) Triethylcarbinyl 2-ethyl-2-isopropylhexanoate was 40H d I I hydrolyzed to form 2-ethyl-2-isopropyl hexanoic acid, yncStabhty (5) 2-ethyl-2-1sopropyl h xan lC 3 11 was Converted toHydrolytic stability was determined by means of saponthe chlonde h 1 1 hification number. The saponification number obtained (6) Y was my medWlt 0n the sample was compared to the theoreticalsaponificae-ethyl-2-1sopropylhexanoyl chloride to form the tion numbenProduct The procedure used a 2 hour reflux of the ester sample In theexamples the expression GLPC refers to gas i g ASTM procedure BT94 wasliquid partition chromatography. This analytical techp y Physical testsnique is adequately described in either of the following publications:

The various physical tests employed ASTM procedures.

TABLE V.II'IYSICAL PROPERTIES OF ESTERS IN EXAMPLES VII-XXII PourKinematic viscosity (cs.) Flash Ester polnt, ASTM point,

F. slope F.

-40 F. 100 F. 210 F.

Di- (2-methyl-Zethylpeutyl) 2,2,8,8-tetraethylazelate -20 144. 3 9. 500. 847 465 Di-(2,2-dimethylhexyl)2,2,8,8-tetraetl1ylaz late -25 106. 18. 47 0.830 450 Di- (2,2-dimethyl0ctyl) 2,2,8,8-tetraethylazelate -4093. 91 8.82 0. 776 460 Di-(2,2-dimethyldecyl)2,2,8,8-tetraethy1azelate-45 112. 7 10. 51 0. 742 495Di-(2,2-dimethylhexyl)2,2,6,6-tetramethylpimelate 44, 822 20. 56 3.710.813 380 Di-(1H,1H,7H-dodecafluor0-1-heptyl)2,2,8,8-

tetraethylazelate -20 105. 47 7. 27 0. 900 Di(2,2dimethyloetyl)3,3-dimethylg1utarate -05 13, 282 20. 83 3. 93 0. 775Di-(2,2-dimethylhexyl)3,3,6,6-tetramethylsuberate 30, 000 41.13 5. 55 0.790 Di-(2,2-dimethylhexy1)2,8-dirnothyl-2 8-Clipropylazelatc -40 69. G46. 67 0. 842 2methyl-2-ethyl-1,3-propanodi0l di-(2-2,di-

ethylpentanoate) -40 32. 98 4. 43 852 Z-methyl-Z-ethyl-l,3-propanedioldi-(2ethy1-2- isopropylhexanoato) -40 109. 4 7. 97 862 1 Data notobtained.

TABLE IX.-DATA ON THERMAL STABILITY IN STEEL PRESSURE CYLINDER ESTERS OFEXAMPLES VII-XXII Viscosity at 100 F. (03.)

Acid num- Percent Ester ber increase decomposi- Original Final Percenttion 2 change Di- 2 Z-dimeth lhex l 2 2 8 S-tetraeth laze-Di-(2,2-dimethylhexyl)3,3,6,6-tetrarnethyl suberate 41. 13 40. 85 0.7 1. 3 0. 5 Di-(2,2-dimethyloctyl)3,3-dimethylglutarate. 20. 83 19. 516. 3 2. 1 0.8 Di-(1H,1H,7H-dodecafluor0-1-heptyl)2,2,8,8-

tetraethylazelate 105. 45 93. 27 11. 6 2. 8 2. 4 Di-(isooctyl) azelate12. 58 10. 94 -13. 0 32.4 11.9 EDi-(2-ethylhexyl) sebacate 12. 59 11.63-7. 6 30. 2 11.5 Di-(2,2-diethylpenty1) azelat 25. 32 11.96 --52. 8 58.1 22. 8 2-methyl-2-ethyl-1,3-propane ethylpentanoate) 32. 98 31. 91 -3.2 5. 4 1. 9

1 A -ml. sample is maintained at 600 F. (316 C.) for six hours undernitrogen. 2 Percentage decomposition=100 (acid numberincrease)/(theoret1cal saponificatlon number).

TABLE X.PHYSICAL PROPERTIESESTE RS OF EXAMPLES XXIII-XXVII Viscosity incentistokes ASTVI Poutr Fliasli 1 pom p0 n slope F. F. 40 F. 100 F. 210F.

2,2-dimethylvalerates:

2-ethyl-2-loutyl-1,3-propanediol 10, 610 13. 41 2. 87 0. 82 65 3302,2,5,5-tetramethyl-1,G-hexanediol 20,280 17.72 3. 48 0.80 70 3452-methyl-2-ethylhexanoates:

2-methyl-2-propyl-1,3-propanediol 23. 88 3. 67 0. 87 60 3752,2,5,5-tetramethyl-1,fi-hexanediol 46. 15 5. 22 0. 86 -60 3802-2-dimethyltetradecylate: 2-methyl-2-propyl- 1,3-pr0panediol 10,61636.82 6.35 0. 69 -55 485 1 Viscosity at F.

TABLE XI-THERMAL AND HYDROLYTIC STABILITY from the dro in funnel at arate which maintained en- DATA ESTERS OF EXAMPLES XXIII-XXVII fie reflux(gopfilingutes) g 2 2 th 1 mates The reaction was refluxed for 30minutes, and then 1 lme y Va liter of tetrahydrofuran was distilled fromthe flask with stirring. The flask was cooled with an ice bath; then -2-2, t ilgrfi fil gfifi i ifig ifi 40 300 ml. of H 0 were added, verycarefully at first, foldiol lowed by 150 ml. of concentrated sulfuricacid in 1 liter of water and finally by 600 ml. of ether. $5- M6 In aseparatory funnel, the water phase was drawn oif Percent chang 1 vis anddiscarded. The ether phase was extracted with 250 ggg g gggg -g -i; ml.of 10 percent sodium bicarbonate. Acidification of Hydrolytic stabilitthe bicarbonate extract gave 31.5 grams of unreacted acid. 15 minutes:

saponificafion NO 20.9 2M This was lmmedlately reduced by the procedureust Iercent saponification 7. 2 7. l e I 30 gggfgh No 39 0 96 0 Theether solutions from both reductions were com- Percent saponification1314 9:3 bined, dried with sodium sulfate and calcium chloride,

Example XXIII.Preparati0n 0f 2-ethyl-2-butyl-1 ,3- propanediol ester of2,2-dimethylvaleric acid The preparation of the acid employed aprocedure similar to that used in Example VII, with the exception that amonobromide, instead of a dibromide, was used.

The glycol used was commercially available.

The esterification procedure was similar to that used in Example IX.

Example XXIV.Preparati0n of 2,2,5,5-letmmethyl-I,6-

hexanediol ester of 2,2-dimethylvaleric acid dropping funnel, and refluxcondenser with drying tube,

36 grams (0.95 mole, metal hydrides) of lithium aluminum hydride wereslurried in 600 ml. of dry tetrahydrofuran. While the slurry was rapidlystirred, 126.2

grams (0.625 mole) a,a,a',a'-tetramethyladipic acid dissolved in 1,150ml. of dry tetrahydrofuran were added and stripped of ether. Theproduct, a tan solid, was distilled in a Koelsch flask at 0.5 mm. Theyield of white, waxy material, M.P. 7679 C., was 76.8 grams (0.441 mole,71 percent).

No carbon-hydrogen analysis was made of this new diol itself, but thecomposition of its pivalate ester was determined and found to check withthe theoretical value.

The ethyl ester of a,a,a',a-tetramethyladipic acid was also made andreduced to the diol.. A solution of 35 grams (0.173 mole) of the crudeacid, 300 ml. of absolute ethanol, and 5 ml. of concentrated sulfuricacid was refluxed for 14 hours and poured into a separatory funnel withether and water. After extraction with 10 percent NaI-ICO and drying,the ether solution was stripped of ether. Distillation through a shortVigreux column gave 28.5 grams (0.111 mole, 64 percent) of colorlessliquid, B.P. 92-94" at 2 mm.

Using a 1-liter, 3-necked flask equipped with Trubore stirrer, refluxcondenser, and dropping funnel, 28.5 grams (0.111 mole) of the esterwere added at reflux rate to a slurry of 4.5 grams (0.119 mole, metalhydrides) of lithium aluminum hydride in ml. of ether. The mixture wasrefluxed for 30 minutes after the addition. About 40 ml. of H 0 wereadded carefully to the cooled flask, followed by 22 ml. of concentratedsulfuric acid in 200 29 ml. of H 0. The resulting ether solution ofproduct was worked up just as in the acid reduction. The yield of diol(undistilled) was 17.6 grams (0.101 mole, 91 percent).

The esterification procedure was similar to that used in Example IX.

Example XXV-Preparation f 2-methyl-2-pr0pyl-L3- propanediol ester ofZ-methyl-Z-ethylhexanoic acid The preparation of the acid employed aprocedure similar to that used in Example VII, with the exception that amonobromide, instead of a dibromide, was used.

The glycol used was commercially available.

The esterification procedure was similar to that used in Example IX.

Example XX VI.Preparati0n of 2,2,5,5-tetrwmethyl-l,6- hexanediol ester 02-methyl-2-ethylhexan0ic acid The preparation of the acid employed aprocedure simi lar to that used in Example VII, with the exception thata monobromide, instead of a dibromide, was used.

The preparation of the glycol is described in Example XXIV.

The esterification procedure was similar to that used in Example IX.

Example XXVlI.-Preparati0n of 2-methyl-2-pr0pyl-1,3- propanediol esterof 2,2-dimethyltetradecanoic acid The preparation of the acid employed aprocedure similar to that used in Example VII, with the exception that amonobromide, instead of a dibromide, Was used.

The glycol used was commercially available.

The esterification procedure was similar to that used in Example IX.

While particular embodiments of the invention have been described, itwill be understood, of course, that the RH O R:

where R is an acyclic alkyl group of from 1 to 4 carbon atoms, R is anacyclic alkyl group of from 1 to 10 carbon atoms, R is an acyclic alkylgroup of from 1 'to 4 carbon atoms and n is an integer of from 1 to 9.

2. The chemical compound di-(2,2-dimethylhexyl)-3,3,6,6-tetramethylsuberate.

References Cited by the Examiner UNITED STATES PATENTS 8/58 Airs et al.260485 9/58 Henne et al. 260485 6/59 Blake et al. 260-485 8/62 Emrick260--410.6

OTHER REFERENCES Asano et al.: Chemical Abstracts, vol. 45, p. 56170(1951).

Birch et al.: Chemical Abstracts, vol. 47, p. 1031d (1953).

LORRAINE A. WEINBERGER, Primary Examiner.

1. CHEMICAL COMPOUNDS HAVING THE FORMULA